Reversible energy absorbing bumper system

ABSTRACT

An energy absorbing, reusable and reversible system for absorbing substantially longitudinal impact forces and dissipating the impact energy therefrom. The bumper system includes an impact frame having pre-contoured rib members which are distended in a radial direction when the impact forces are applied to the system. A resilient sleeve surrounds the impact frame to absorb energy and force the rib members to their initial unloaded contour. Energy absorption is accomplished through a combination of loading the rib members into or near the plastic stress region and the resiliency of the surrounding sleeve.

United States Patent 1191 Sergay 1 51 Apr. 3, 1973 1 REVERSIBLE ENERGYABSORBING 363,658 12/1931 Great Britain .293/86 BUMPER SYSTEM Inventor:Dimitry B. Sergay, 427 Dorothy Drive, King of Prussia, Pa, 19406 Filed:Mar. 12, 1971 Appl. No.: 123,759

US. Cl ..267/l40, 293/88 Int. Cl. ..Fl6f 7/00 Field of Search ..293/85,86, 87, 88; 267/30,

References Cited UNITED STATES PATENTS 12/1931 Deveaux ..293/88 2/1970Fitzgerald et a1. 4/1952 Lockwood 1/1968 Ludwikowski ..293/85 FOREIGNPATENTS OR APPLICATIONS 1/l963 Great Britain ..267/l51 PrimaryExaminer-James B. Marbert Assistant Examiner-Robert SaiferAttorney-Maleson, Kimmelman and Ratner and Morton J. Rosenberg [5 7]ABSTRACT An energy absorbing, reusable and reversible system forabsorbing substantially longitudinal impact forces and dissipating theimpact energy therefrom. The bumper system includes an impact framehaving precontoured rib members which are distended in a radialdirection when the impact forces are applied to the system. A resilientsleeve surrounds the impact frame to absorb energy and force the ribmembers to their initial unloaded contour. Energy absorption isaccomplished through a combination of loading the rib members into ornear the plastic stress region and the resiliency of the surroundingsleeve.

20 Claims, 5 Drawing Figures PAIENIEDAPR3 I975 3,724,833

INVENTOR DIM/TRY B. SERGAY WJM ATTORNEY REVERSIBLE ENERGY ABSORBINGBUIVIPER SYSTEM BACKGROUND OF THE INVENTION l Field of the InventionThis invention relates to the field of energy absorbing devices. Inparticular, this invention pertains to the field of reusable andreversible systems for energy absorption. More in particular, thisinvention relates to the field of energy absorbing bumper systems foruse on moveable vehicles possibly subjected to impact forces.

2. Prior Art Energy absorbing bumper systems are known in the art,however most systems shown in the prior art provide for singulardisplacement direction spring members to absorb and dissipate theenergy. Such prior art does not permit a transferral in direction of anyload characteristics imposed on these systems.

In some prior art elastomeric materials are used to cushion a directimpact force. These prior art devices does not provide for a resilienthousing to initially surround the enlargements and therefore provideradial compressive action on the enlargements after the force impact fora cyclical completely automatic operation.

In some prior art systems, apparatus are provided wherein actuation isprovided through compressive fluid escape, hydraulic mechanisms andfluid drive. Such systems in some cases are reusable and reversible butdo not include a compact, substantially maintenance free mechanism whichis easily manufactured at low cost as in the present invention.

SUMMARY OF THE INVENTION It is an object of the subject invention toprovide an energy absorbing, reusable system for dissipating ener- 83'-It is a further object of the present invention to provide an energyabsorbing mechanism that is reversible after an impact force has beenrelieved to allow the automatic return of the mechanism to its originalgeometricalcontour.

Another object of the subject invention is to provide a bumper systemfor use on a moveable vehicleto be used in conjunction with a faceplateor bumper or as a primary impact loader.

A still further object of the present invention is to provide a bumpersystem which is easily manufactured, of low cost and is compact for easeof installation on moveable vehicles.

A reversible energy absorbing bumper system which includes an impactframe to be outwardly extendable from a longitudinal axis of the framewhen a substantially longitudinal force is applied to the bumper system.A resilient shroud receives and compresses the impact frame when theframe is extended outwardly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a pair ofenergy absorbing bumper systems attached on opposing ends to a vehicleframe and a faceplate; I

FIG. 2 is an elevation sectional view of the energyabsorbing system inan initial or unstressed condition taken along the section line 2-2 ofFIG. 1;

FIG. 3 is an elevational section view of the energy absorbing system ina compressively stressed condition;

FIG. 4 is a cross-section view of the energy absorbing system takenalong the section line 4-4 of FIG. 2; and

FIG. 5 is an exploded perspective illustration of the energy absorbingsystem.

DESCRIPTION OF THE PREFERRED EMBODIMENT I Referring now to FIGS. 1, 2,and 3 there is shown energy absorbing cell, or bumper system 10 toprovide a reusable and reversible mechanism which absorbs and dissipatesenergy when impacted by a force in substantially longitudinal direction12. An impact force causes a compression deflection of cell 10 indirection 12 as well as in an outwardly directed radial dimension 16.When the force is removed, system 10 returns to its original unstressedcondition dimensions. The component deforming elements of system 10include impact frame or liner 14 and resilient shroud or elastic housing18 which is radially 16 stressed and longitudinally 12 compressed uponinception of the impact force. Shroud 18, as will be discussed in detailin following paragraphs is composed of a high density cellular materialwhich being elastic in nature absorbs and dissipates the impact energyand then forces system 10 in a reversal cycle to its unstresseddimensions.

In use, bumper system 10 may be attached to bumper guard, or face plate20 of a vehicle on a first end 24 and secured to vehicle frame 21 atsecond end 22. As is shown in FIG. 1, cells 10 may be positioned at aplurality of points along inner circumference 23 of faceplate 20dependent upon the particular application desired. In this concept, aforce applied to outer circumference 25 of bumper 20 may be transmittedto a multiplicity of cells 10. In other forms, system 10 may be used inunitary fashion to singularly absorb the energy characteristics of asubstantially longitudinal impact force.

In the basic conceptual model bumper system 10 incorporates the loadingof a high density cellular housing 18 through radial expansion of asteel interliner. In addition, the radially expanding steel liner alsomay absorb impact loading energy when loaded in the plastic region athinge lines or apexes 46 as will be discussed in detail. In this mannersystem 10 provides optimized energy absorption characteristics as afunction of impact load and system deflection.

As shown in FIGS. 2, 3, and S, impact frame or liner 14 includes firstand second impact members 26, 28 rib or extension members 30 passing insubstantially longitudinal direction 12 being rigidly secured onopposing ends thereof to first and second impact members 26, 28.Additionally, impact frame or liner 14 also defines ring supports 32having an annular contour as described in FIG. 5. Annular rings 32include through openings or passages 34 substantially equal in diameterto the external diameter of first and second impact members 26, 28. Asshown, each bumper system or energy absorbing cell 10 operably includesa pair of longitudinally opposing annular rings 32. In construction,rings 32 are mated or fitted to lateral walls 36, 38 of first and secondimpact members 26, 28 to permit contiguous interfacing between innerannular wall 40 and lateral wall surfaces 36, 38. Material constructionof rings 32 constitute a composition of mild or spring steel, or likematerial able to withstand the imposed forces. Illustrative sizing ofrings 32 adapted for use on faceplate or bumper 20 provides an innerannular diameter of approximately 2.5 inches and an external diameter of4 inches with lateral walls 27 having an approximate length of 0.75inches. However, such sizing of cells 10 are dependent on a particularfunction of materials and impact force not important to the basicinventive concept.

First and second impact members 26, 28 are displaced from each other inlongitudinal direction 12, however, they are aligned with respect toeach other along a longitudinal axis of cell 10. Impact members 26, 28are disk shaped in geometrical contour having upper and lower basesurfaces 42, 44 with lateral walls 36 providing a specified thicknessfor members 26, 28 wherein rib or extendable arms 30 may be rigidlysecured on opposing ends thereof to peripheral walls 36. In general,members 26, 28 may be formed geometrically in a manner such that thecross-sectional area plane normal to longitudinal direction 12 defines amany sided polygon or other like symmetrical configuration such as acircle as shown. The only restriction in the contouring of members 26,28 being that such be compatible with equal angular spacing of arms 30circumferential to walls 36. In construction, members 26, 28 may be madeof a variety of steel based materials or like compositions sufficient towithstand the imposed forces and maintain the structural integrity ofunit 10. Opposing impact members 26, 28 have an external diametersubstantially, equal to but slightly less than ring supports 32 forinsertion and mating of corresponding lateral surfaces 36 and 40.

Rib or extension members 30 extend substantially longitudinal between,and are rigidly secured to first and second impact members 26, 28. Asshown in FIG. 4 the plurality of ribs 30 are positioned around thecircumference of lateral walls 36, angularly displaced in an equalmanner about the peripheral boundary. For illustrative purposes, FIG. 4details six rib members 30 displaced angularly at 60 to a nextconsecutive member, however, such displacement is a function ofthenumber of ribs 30 used and isnot important to the inventive conceptas herein defined. In this manner, rib members 30 determine the radialexpansion properties of system 10.

Each of arms 30 have an outwardly directed apex 46 with respect tolongitudinal direction 12 at a location substantially mid-point to thedisplaced distance between first and second members 26, 28. As formed,apex angle 48 is directed to allow outward translation of arms 30 whenan impact load is applied to system 10 in substantially longitudinaldirection 12. Apex angle 48 is found through experimental tests to beoptimally effective when formed within a range of -l5, however such ishighly dependent upon the material properties of arms 30. Dimensionally,arms 30 define a rectangular cross-section approximately 5.5 inches inlength and 0.5 inches in width.

Ribs 30 are rigidly secured to opposing impact members 26, 28 throughbolts 50, weld, adhesive securement or other such means not important tothe inventive concept. In construction, members 30 may be composed ofmild or spring steel'or like material which permits reversible expansionof arms 30 in radial direction 16.

Ring support or annular element 32 having an internal diameter ofthrough opening, 34 slightly greater than the external diameters ofimpact members 26, 28 i is slideable inserted over corresponding lateralwalls 36. Rings 32 may after insertion be'welded or otherwise rigidlysecured to lateral walls 36 thus providing a unitary, rigidly securedassembly 10. As previously described, it is preferred to form rings 32of the same, or similar material as that described for impact members26, 28 to insure similar compressive loading characteristics overassembly or cell 10.

Resilient shroud, elastic housing or elastomeric cylinder 18 includeslongitudinally directed through passage 52 as detailed in FIG. 5. Impactframe 14 is inserted within passage 52 for releasably securing liner 14to housing 18. The internal diameter of passage 52 of resilient shroud18 is substantially equal to the external diameters of impact members26, 28. Housing 18 being elastic in nature, is deformable in outwardradial direction 16 to permit insertion of apexes 46 of ribs 30 througha force fitting. Housing lateral wall 62 is sloped from a maximum wallthickness at apex 54 to a minimum wall thickness at opposing end housingsurfaces 56, 58. Apex 54 is located approximately longitudinallymid-point between the length. of housing 18. Housing apex angle '60approximates an angular arc of 15, however, such is not important to theinventive concept herein described. Lateral wall 62 therefore providesan inclined outer surface extending from opposing surfaces 58, 56 .toapex 54. In a plane normal to longitudinal direction 12, it is seen thathousing 18 takes the contour of an annulus. Upon insertion of impactframe 14 within housing 18, rib apexes 46 are radially aligned withhousing apex 54. As shown in FIG. 2 the longitudinal dimension ofhousing 18 substantially approximates the displacement distance betweenring supports 32 and annularly interfaces thereto on lower surfaces 64,66. In final assembly, housing 18 interfaces with and is contiguouslongitudinal to arms 30 of impact fi'ame l4 and as has been described,annularly with ring supports 32 to form a one piece energy absorbingcell 10.

Annularly shaped housing 18 is constructed of a high density cellularmaterial such as polyurethane having a density range between 10 and '80pounds per cubic foot. The aforementioned density range includes acompressive strength between approximately 300 and 5,000 pounds persquare inch. Under compressive stress such material constructionresponds to a broad range of load bearing or cushioning properties. Inaddition, such materials show a great resistance in breakdown to arepeated stretching or deflection. I

In operation, bumper system or energy absorbing cell 10 is impacted witha force substantially longitudinally directed 12. This force may bethrough direct interface or transmitted through faceplate or bumper 20as shown in FIG. 1. In normal operating procedure, system may bearranged in symmetrical relation to a longitudinal axis passing normalto the plane of faceplate in a plurality of positionings. Theaforementioned and described arrangement and specific number of systems10 to be used are dependent on the particular structural requirementsand loading bearing characteristics for a predetermined condition. Animpacting force provides for a compressive deflection in direction 1 2forcing a decrease in the longitudinal displacement between first andsecond impact members 26, 28. The compressive deflection imparts thenecessary drive to expand arms 30 in radial direction 16 against elastichousing 18. Resilient shroud 18 being outwardly stretched or deflectedabsorbs a portion of the energy imparted by the impact force. Afterremoval of the impact force, elastic housing 18 provides the necessarycompressive force to reposition arms 30 in their original unstressedgeometrical contour. From the above discussion, it is seen that themajor proportion of the impact force energy is removed through stressingarms 30 into the plastic range as well as through housing 18 absorption.In this manner, the cycle of energy absorbing cell 10 is reversible andis prepared for a next impacting load stress.

In a basic description of system 10, the concept entails the loading ofcylinder 18, made of an elastomeric material, through radial expansionof arms 30. Ribs 30 are forced in the proper direction when acompressive or substantially longitudinal force is imparted to theprestressed specific contour as shown. Arms 30 when radially expanded16, are loaded into their plastic region at apex 46. Once arms 30 aretransferred to an outward displacement, the loading of the high densitypolyurethane foam sleeve 18 is stressed sufficiently to force arms 30 totheir original position thus allowing energy absorption combined withreversibility to insure a reusable system 10.

As is seen in FIG. 1, system 10 may be secured to faceplate 20 andcorresponding vehicle frame 21 through a variety of fastenings. Althoughsuch fastening means are not important to the inventive concept, suchmay be incorporated through bolts directed into first and second impactmembers 26,28. Other variations of securing system 10 to rigid members20, 21 include welding, flange attachments and possible adhesive contactor some combination of the aforementioned methods.

In order to stiffen and control the location of plastic hinge lines orapexes 46 of ribs 30 other variations present themselves to thoseskilled in the art. Ribs 30, for instance, may be constructed of smalldiameter steel tubing and crimped at bend lines 46. Crimping of arms 30may also be accomplished on opposing sides of apexes 46 to provide amore complete control of the plastic hinge lines when stressed by animpact load.

The invention herein described has been shown to be an effective,reversible energy absorbing system which provides absorption of highloadings with an easily manufactured, low cost apparatus. While theinvention has been described with a certain specific embodiment thereof,it will now be understood that further modifications will suggestthemselves to those skilled in the art, and it is intended to cover suchmodifications within the scope of the appended claims.

What is claimed is:

1. A reversible energy absorbing bumper system,

comprising:

a. an impact frame including at least one substantially longitudinallydirected arm having an unloaded elongated extension, said extensionbeing adapted to extend outwardly from a longitudinal axis of said framewhen a force having a longitudinal component is applied to said bumpersystem; and,

b. shroud means of an elastomeric material for receiving said impactframe, said shroud means being the primary restoring means for restoringsaid frame to said unloaded extension after said impact frame isextended outwardly.

2. The bumper system as recited in claim 1 wherein said impact framecomprises:

a first and second impact member being longitudinally displaced fromeach other, said arm defining an extension means being rigidly securedto said first and second impact members on opposing ends of saidextension means.

3. The bumper system as recited in claim 2 wherein said impact frameincludes a pair of ring elements having through openings, said first andsecond impact members insertable within said through openings andrigidly secured thereto.

4. The bumper system as recited in claim 2 wherein said first and secondimpact members include cylindrical disk elements, said impact membersbeing axially aligned with respect to said longitudinal axis.

5. The bumper system as recited in claim 2 wherein said first and secondimpact members define a pair of disc members having a predetermineddiameter and longitudinally dire'cted thickness.

6. The bumper system as recited in claim 2 wherein said arm comprises anexpandable element which extends substantially longitudinal between andrigidly secured to said first and second impact members, said expandableelement having an outwardly directed apex with respect to saidlongitudinal axis at a predetermined location substantially midpointbetween said first and second impact members.

7. The bumper system as recited in claim 2 wherein said extension meanscomprises a plurality of translatable elements having opposing endsrigidly secured to a peripheral surface of said first and second impactmembers respectively, said translatable elements having a monotonicallydecreasing contour from a location sub stantially midpoint between saidimpact members and being translatable in an outward direction withrespect to said longitudinal axis when said force having saidlongitudinal component is applied to said bumper system.

8. The bumper system as recited in claim 7 wherein said plurality oftranslatable elements are angularly oriented substantially equidistantfrom each other around said periphery of said impact members.

9. The bumper system as recited in claim 1 wherein said shroud meansincludes an elastic housing having a longitudinally directed throughopening, said impact frame being insertable within said through openingfor releasably securing said impact frame to said elastic housing.

10. The bumper system as recited in claim 9 wherein said elastic housingis constructed of a cellular material, said housing being annularlyshaped in a cross-sectional plane normal to said longitudinal axis.

11. The bumper system as recited in claim 10 wherein said annularly.shaped housing defines a pair of opposing longitudinal end surfaces,said housing having a radial wall thickness monotonically increasing toa maximum thickness substantially midpoint of said opposing longitudinalend surfaces.

12. The bumper system as recited in claim 10 wherein said annularlyshaped housing is constructed of a high density cellular material.

The bumper system as recited in claim 12 wherein said annularly shapedhousing is constructed of a high density polyurethane material.

14. The bumper system as recited in claim 13 v wherein said housingisconstructed of a polyurethane loads as recited in claim 15 wherein thestep of displacing said substantially rigid impact frame is preceded bythe step of applying a force to said impact frame, said force having acomponent in said longitudinal direction.

17. The method for reversibly absorbing bumper loads as recited in claim16 wherein the step of displacing said substantially rigid impact frameincludes the step of longitudinally. compressing said impact frame apredetermined distance responsive to said applied force.

18. The method for reversibly absorbing bumper loads as recited in claim17 wherein the step of displacing said substantially rigid impact frameincludes the step of outwardly extending said impact frame from alongitudinal axis of said frame when said force is ap plied. 1

19. The method for reversibly absorbing bumper loads as recited in claim15 wherein the step of compressing said shroud member includes the stepof displacing said shroud member in a direction substantially transversesaid longitudinal direction.

20; The method for reversibly absorbing bumper loads as recited in claim19 wherein thestep of compressing said shroud member includes the stepof Iongitudinally compressing said shroud member a predetermineddistance.

1. A reversible energy absorbing bumper system, comprising: a. an impact frame including at least one substantially longitudinally directed arm having an unloaded elongated extension, said extension being adapted to extend outwardly from a longitudinal axis of said frame when a force having a longitudinal component is applied to said bumper system; and, b. shroud means of an elastomeric material for receiving said impact frame, said shroud means being the primary restoring means for restoring said frame to said unloaded extension after said impact frame is extended outwardly.
 2. The bumper system as recited in claim 1 wherein said impact frame comprises: a first and second impact member being longitudinally displaced from each other, said arm defining an extension means being rigidly secured to said first and second impact members on opposing ends of said extension means.
 3. The bumper system as recited in claim 2 wherein said impact frame includes a pair of ring elements having through openings, said first and second impact members insertable within said through openings and rigidly secured thereto.
 4. The bumper system as recited in claim 2 wherein said first and second impact members include cylindrical disk elements, said impact members being axially aligned with respect to said longitudinal axis.
 5. The bumper system as recited in claim 2 wherein said first and second impact members define a pair of disc members having a predetermined diameter and longitudinally directed thickness.
 6. The bumper system as recited in claim 2 wherein said arm comprises an expandable element which extends substantially longitudinal between and rigidly secured to said first and second impact members, said expandable element having an outwardly directed apex with respect to said longitudinal axis at a predetermined location substantially midpoint between said first and second impact members.
 7. The bumper system as recited in claim 2 wherein said extension means comprises a plurality of translatable elements having opposing ends rigidly secured to a peripheral surface of said first and second impact members respectively, said translatable elements having a monotonically decreasing contour from a location substantially midpoint between said impact members and being translatable in an outward direction with respect to said longitudinal axis when said force having said longitudinal component is applied to said bumper system.
 8. The bumper system as recited in claim 7 wherein said plurality of translatable elements are angularly oriented substantially equidistant from each other around said periphery of said impact members.
 9. The bumper system as recited in claim 1 wherein said shroud means includes an elastic housing having a longitudinally directed through opening, said impact frame being insertable within said through opening for releasably securing said impact frame to said elastic housing.
 10. The bumper system as recited in claim 9 wherein said elastic housing is constructed of a cellular material, said housing being annularly shaped in a cross-sectional plane normal to said longitudinal axis.
 11. The bumper system as recited in claim 10 wherein said annularly shaped housing defines a pair of opposing longitudinal end surfaces, said housing having a radial wall thickness monotonically increasing to a maximum thickness substantially midpoint of said opposing longitudinal end surfaces.
 12. The bumper system as recited in claim 10 wherein said annularly shaped housing is constructed of a high density cellular material.
 13. The bumper system as recited in claim 12 wherein said annularly shaped housing is constructed of a high density polyurethane material.
 14. The bumper system as recited in claim 13 wherein said housing is constructed of a polyurethane material having a density range between 10 and 80 pounds/cu.ft.
 15. A method for reversibly absorbing bumper loads including the steps of: a. displacing a substantially rigid impact frame having a predetermined longitudinally directed unloaded geometric configuration; b. compressing a shroud member of elastomeric material, said shroud member surrounding and being contiguous to said impact frame; and, c. forcing said impact frame to said unloaded geometric configuration primarily through a transverse compressive force of said shroud member acting on said impact frame.
 16. The method for reversibly absorbing bumper loads as recited in claim 15 wherein the step of displacing said substantially rigid impact frame is preceded by the step of applying a force to said impact frame, said force having a component in said longitudinal direction.
 17. The method for reversibly absorbing bumper loads as recited in claim 16 wherein the step of displacing said substantially rigid impact frame includes the step of longitudinally compressing said impact frame a predetermined distance responsive to said applied force.
 18. The method for reversibly absorbing bumper loads as recited in claim 17 wherein the step of displacing said substantially rigid impact frame includes the step of outwardly extending said impact frame from a longitudinal axis of said frame when said force is applied.
 19. The method for reversibly absorbing bumper loads as recited in claim 15 wherein the step of compressing said shroud member includes the step of displacing said shroud member in a direction substantially transverse said longitudinal direction.
 20. The method for reversibly absorbing bumper loads as recited in claim 19 wherein the step of compressing said shroud member includes the step of longitudinally compressing said shroud member a predetermined distance. 